[Detection of Aspergillus infection in blood of malignant hematopoietic tumor patients by two-step polymerase chain reaction].

Objective: To investigate the sensitivity and specificity of two-step PCR in detection of Aspergillus species in blood from malignant hematopoietic tumor patients.

Methods: Forty-one blood samples from high-risk patients were detected with two-step PCR. The clinical applicability was assessed with analyzing computed tomography, Aspergillus culture, neutropenia and outcome after anti-fungal therapy.

Results: Specific band of PCR was obtained from Aspergillus strains and products of PCR had a high homogeneous in sequence with Aspergillus species. Sixteen of 41 patients were PCR positive and controls were all PCR negative. Among PCR positive patients, 4 patients had positive cultures. The lowest WBC count was (0.30 +/- 0.14) x 10(9)/L and (0.50 +/- 0.26) x 10(9)/L respectively and duration with WBC count less than 1.0 x 10(9)/L was (19.00 +/- 8.31) days and (12.69 +/- 6.95) days respectively in the two groups. After antifungal therapy, one of the patients with PCR positive died of chemotherapy-related early death.

Conclusions: The two-step PCR assay allows for highly sensitive and specific detection of Aspergillus pathogens in vitro and in vivo. The detection with PCR has some value in the early diagnosis and helps us to make decision for antifungal therapy.